The area of laser processing of materials encompasses a wide variety of applications that involve cutting, drilling, milling, welding, melting, etc. and different types of materials. Among these applications, one that is of particular interest is cutting or separating different types of substrates, for example on a process to separate thin film transistor (TFT) glass compositions.
From process development and cost perspectives there are many opportunities for improvement in cutting and separation of glass substrates. It is of great interest to have a faster, cleaner, cheaper, more repeatable and more reliable method of glass separation than what is currently practiced in the market today. Among several alternative technologies, laser separation has been tried and demonstrated using different approaches. The techniques range from: 1) actual removal of material between the boundaries of the desired part (or parts) and its matrix; 2) creation of defects within the bulk of the material to weaken or seed it with cracking initiation points along the perimeter of the desired profile followed by a secondary breaking step; 3) propagation of an initial crack by thermal stress separation. These laser cutting processes have demonstrated the potential economic and technical advantages such as precision, good edge finish, and low residual stress compared to competing technologies (mechanical scribing and breaking, high pressure water jet and ultrasonic milling, etc.).